We report the first charge-state measurements of fast heavy ions passing through a plasma target. The projectiles were ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ ions at an energy of 4.8 MeV/amu and ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ ions at an energy of 5.9 MeV/amu. The target was a 20-cm-long Z pinch discharge which provided fully ionized hydrogen plasma with free electron densities up to 1.5×${10}^{19}$ ${\mathrm{cm}}^{\mathrm{-}3}$. The measured charge-state distributions are in excellent agreement with theoretical calculations. For Xe ions an increase of the ion charge state in plasma over the charge state in cold gas was observed.

• Received 27 February 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.3623